docs: fix inaccurate statements and broken examples across adev - #71131

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/main/contributing-docs/commit-message-guidelines.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• angular.dev application / infrastructure changes
• Other... Please describe:

What is the current behavior?

Issue Number: N/A

Several adev pages have examples that don't compile or fail at runtime, API names that don't exist, and statements about defaults or behavior that no longer match main. I checked each case against the source, public API goldens, or the CHANGELOG.

Forms, signals and HTTP

• Fixed examples with a stray | after selector, constructor(): void, an undeclared enable in a custom validator, combineLatest imported from rxjs/operators but subscribed to, map used in an interceptor that returns nothing, a missing BasicInput import, and a fetch result returned as Promise<User> without calling .json().
• HttpValidatorOptions.options is HttpResourceOptions, so headers and timeout belong in the request object.
• FormGroupNameDirective and FormArrayNameDirective don't exist; the APIs are FormGroupName and FormArrayName. FieldContext.field and DisabledReason.field were renamed to fieldTree (729b964), and the fetch response property is responseType, not type.
• resource.value() throws in the 'error' state (Gated Resource API changes #61441); earlyRead receives the cleanup function; submit() doesn't wait for pending validators; an in-progress submission blocks the form and its descendants, not its parents; and with the fetch backend, timeouts are TimeoutError DOMExceptions while network errors are the error thrown by fetch.

Routing, DI and components

• runInInjectionContext is a standalone function, not an Injector method. The root-level singleton example imported Injectable but used @Service(), and the "class constructor" example tried to read an injected field from a field initializer.
• NullInjectorError is reported as NG0201. PlatformModule doesn't exist, and platformBrowserDynamic is deprecated.
• contentChild traverses descendants by default; only contentChildren doesn't. NO_ERRORS_SCHEMA also exists.
• Fixed router examples with a route pattern that never matches ('user/:id/'), a missing quote in redirectTo, out-of-scope queryParams and id(), an invalid spread inside Routes, an untyped isActive configuration, and an invalid import statement.
• ActivatedRoute.url emits UrlSegment[]; routerLinkActive doesn't set aria-current without ariaCurrentWhenActive; and unset routerOutletData gives undefined.

Testing, templates and other guides

• fakeAsync works with Vitest through zone.js/plugins/vitest-patch (feat(zone.js): support vitest patching in zone.js/testing #68395, docs: add information about zone.js Vitest patch in the Vitest migration guide #68422). TestBed is zoneless by default since v21 (fix(core): Remove Zone-based change provider from internals by default #63382), so autoDetectChanges defaults to true; the zoneless guide's TestBed section was updated accordingly.
• TestBed.createDirective() exists (feat(core): add utility for testing directives #70453), while TestBed.get was removed (feat(core): remove TestBed.get #60414). StaticProviders doesn't exist, initTestEnvironment has no compiler factory argument, and output() returns an OutputEmitterRef.
• The custom IdleService example must return a number. input({alias}) uses the alias object as the initial value, and i18n IDs depend on the source text and meaning, not the description.

CLI and reference

• New projects no longer include @angular/animations, @angular/platform-browser-dynamic, or zone.js when using the default zoneless setup, and use @angular/build. cnpm was removed from packageManager, generated files are app.ts/App, deployUrl is supported by the application builder, and ng generate has no --collection option.
• Template type checking with strictTemplates is enabled by default. strictTypeChecks doesn't exist; the relevant option is strictNullChecks. Signal inputs were also being read without calling them in the AOT and template type-checking examples.
• Fixed extended diagnostics examples: NG8111/NG8114 "wrong" examples had been reformatted into the fixed code and are now protected with prettier-ignore; NG8107 referenced fields that don't exist; NG8104's fixed example wasn't valid; and NG02802 used the private withHttpTransferCache.
• The cli-builder example used options rejected by the application builder, and the optimization example showed stylePreprocessorOptions in the wrong place.

Ecosystem, best practices and tutorials

• VersionFailedEvent was reverted (Revert "feat(service-worker): notify clients about version failures (… #65087), so the service worker docs now list four events and the example no longer handles VERSION_FAILED. The navigation request mode is navigate.
• The output interop package is @angular/core/rxjs-interop; rxResource's stream returns an Observable; and OnPush compares inputs with Object.is.
• Resource status is 'resolved', not 'success'. The a11y example was binding a signal without calling it, the essentials guide imported 'profile-photo.ts', and the tutorial examples had fixes for a missing comma, getHousingLocationById, Array.filter, and the fetch URL.

What is the new behavior?

The examples now compile against main, and the statements match the current source and defaults. The changes are kept minimal; table rows were only realigned where required by Prettier.

Does this PR introduce a breaking change?

• Yes
• No

Other information

Docs-only change in adev/src/content. No lines changed by currently open PRs were touched.